Method of preparing blended yarns

ABSTRACT

Blended yarns are prepared by plying and twisting a fibrillated film and an untwisted staple fiber roving. The fibrillated film forms a surface layer to ensheath the roving. The film to be fibrillated can be either of the flat type to form a staplelike surface layer or of striated type to form a continuous filament surface layer.

PATENTED JAN 4 I972 FIG. 3

CHARLES W. KIM INVENTOR BY wan-6m f whim,

ATTORNEY United States atent [72] Inventor Charles W. Kim

Wilmington, Del. [21] Appl. No. 3,165 [22] Filed Jan. 15, 1970 [45] Patented Jan. 4, 1972 [73] Assignee Hercules Incorporated Wilmington, Del.

[54] METHOD OF PREPARING BLENDED YARNS 5 Claims, 4 Drawing Figs.

[52] U.S. Cl 57/160, 57/144 [51] Int. Cl D02g 3/36, D02g 3/00, D02g 3/06 [50] Field of Search 57/ 144, 152,156,160, 163, l67,l68;28/DIG. 1,72

[56] References Cited UNITED STATES PATENTS 3,199,284 8/1965 Seragg 57/167 X 3,378,997 4/1968 Matsui et al. 57/167 X 3,387,450 6/1968 Brown 57/144 X 3,405,516 10/1968 Laureti 28/'1 X 3,460,338 8/1969 Morrison.. 57/152 X 3,495,393 2/1970 Wada et al 57/144 3,496,716 2/1970 Howard et a1. 57/167 X 3,500,627 3/1970 Kim 57/167 X 3,506,535 4/1970 Prevorsek et al. 28/1 X FOREIGN PATENTS 1,090,210 1 l/ 1967 Great Britain 28/ 1 Primary Examiner-Donald E. Watkins Attorney-John W. Whitson ABSTRACT: Blended yams are prepared by plying and twisting a fibrillated film and an untwisted staple fiber roving. The fibrillated film forms a surface layer to ensheath the roving. The film to be fibrillated can be either of the fiat type to form a staplelike surface layer or of striated type to form a continuous filament surface layer.

METHOD OF PREPARING BLENDED YARNS This invention relates to a process of preparing a spunlook" yarn by blending of continuous filaments and staple It has become common practice to blend natural fibers such as cotton and wool with manmade fibers or to blend different types of manmade fibers to obtain a balance of properties in a yarn. The popular polyester-cotton blend employed in the manufacture of mens wash and wear shirts is an example of a yarn of this type. In most cases such yarns are prepared by spinning a homogeneous blend of cotton staple and the synthetic staple.

In accordance with this invention, an improved method of blending fibers to achieve a desired balance of properties has been discovered, which method is simpler and more reliable, and involves less handling of the constitute fibers than is required for the more conventional blending technique. Moreover, the blended yarn produced by this technique exhibits properties of, e.g., strength and bulk not shown by blended yarns prepared as described above. Yarns are prepared according to this invention by a process which comprises plying a fibrillated uniaxially oriented film with a substantially twist-free staple fiber roving of either natural or synthetic fibers, and twisting the plied structure whereby the fibrillated film forms a surface layer ensheathing the roving.

The fibrillated film component employed in the process of this invention can be either a flat film or a striated film. Fibrillation of both these types of film is well known in the art. Fibrillation of a flat film results in splitting of the film in a random, nonuniform manner to produce short length, staplelike fibers. Fibrillation is carried out to an incomplete extent. In this manner, the areas of the film between the splits remain attached to each other at their ends, forming a staple fiber network structure having very few free ends.

A striated film, comprised of relatively thick filament sized striations separated by thin webs, splits readily and almost exclusively in the thin sections when it is fibrillated, leaving the thicker sections virtually intact as continuous backbone filaments and for this reason result in stronger yarns than do the fibrillated flat films. The degree of fibrillation can be regulated to prepare a beam of completely separated, individual monofilaments or a netlike structure in which the individual monofilaments remain partially joined by incompletely severed fibrillar web sections. This incompletely fibrillated form of the striated film is the most preferred form for use in this invention. Fibrillation of either the flat or the striated film can be carried out by a number of known methods such as, e.g., by the use of a rotating beater bar having serrated edges or by subjecting the film to the action of a high velocity air jet.

The invention is illustrated in the attached drawings, in which:

FIG. 1 illustrates one embodiment of the process of the invention;

FIG. 2 illustrates an incompletely fibrillated striated film having a twist-free roving laid thereon for plying;

FIG. 3 illustrates a strand prepared by twisting the plied structure illustrated in FIG. 2; and

FIG. 4 illustrates the product of FIG. 3 after having been subjected to the action of the air jet.

With reference to FIG. 1, a uniaxially oriented striated film l is advanced over a serrated fibrillation means 2, by means of pull rolls 3 and 4, whereby the film is reduced to a plurality of individual continuous filaments 10 as shown in FIG. 2 which are connected to one another by fibrils II and maintained in a single plane as they enter pull rolls 4. As the continuous filament beam enters pull rolls 4, an untwisted staple fiber roving 5 is fed in with it. The structure at this point is illustrated in FIG. 2, which shows the individual filaments I interconnected by means of fibrils 11 in a netlike structure, with the staple-fiber roving laid thereon. The continuous filament beam is then given a twist of about 5% to 15 twists per inch to form a strand or yarn by means of twister 6 and collected into a bundle 7.

Twisting of the structure causes the fibrillated film I to ensheath the staple fiber roving S to form a sheath-core type of structure such as is illustrated in FIG. 3 wherein a continuous filament sheath layer encloses a staple fiber core. The yarn in this state is useful singles yarn which exhibits on its surface the properties of the surface yarn, but in the overall yarn, these properties are modified by those of the staple fiber core. For example, in a yarn of polyester and cotton such as has been mentioned hereinabove, the strength and durability of the polyester are modified by the moisture affinity of the cotton and by its more natural hand. Yarns can be prepared by the technique of this invention and in any desired denier from about 70 to 6,000.

The description of the invention with respect to FIG. 1 has been made in terms of incompletely fibrillated striated film. However, except for specific points such as the presence of continuous filaments, the description can apply equally well to the other forms of fibrillated product, i.e., completely fibrillated striated film or incompletely fibrillated flat film.

In an attractive alternative operation, the yarn is subjected to the action of a high-velocity fluid jet. A yarn treated in this manner is illustrated in FIG. 4. The action of the high-velocity fluid disintegrates the staple fiber roving and entangles the short length staple fibers with the surface filaments 10. The short lengths of staple fiber are caught between the synthetic filaments of the sheath and trapped with many of their ends 12 protruding from the surface of the yarn. The result is a still more uniform blending of the components in a yarn which, due to the presence, on its surface, of the ends of the staple fibers, has the appearance of having been spun. In this alternative, the previously mentioned incompletely fibrillated products are particularly helpful since the presence of the fibrillar residues between the filaments aids in catching and holding the staple fibers, permitting them to protrude from the surface of the yarn but not permitting them to escape. The fluid treatment can be accomplished either before or after the twisting of several yarns together, if a multi-ply yarn is contemplated.

The plied and twisted and, optionally, air jet treated singles yarn can be employed as it is without further treatment or it can be subjected to further optional operations. One such optional operation comprises twisting together two or more of such yarns to form a mult-ply yarn of greater denier. In accomplishing such plying, the two or more singles yarns are twisted by conventional textile twisting techniques to a level of about A to 15 twists per inch, but the twist inserted will be reverse to the twist of the individual plies. The reversal of the twist balances the original torque occasioned by the initial twisting of the yarn, as well as forming the two single yarns into a coherent ply yarn.

The continuous filaments employed in the invention, can, also, if desired, be crimped by conventional mechanicalcrimping techniques prior to plying with the staple-fiber roving. Conventional stuffing box crimpers can be employed for this purpose. It is also possible to effect crimping or bulking of the continuous filaments by means of the stuffer box following plying and twisting with the roving. Alternatively, bulking can be effected by means of the air jet which is employed to disintegrate the roving. In yet another alternative the filaments can be of bicomponent configuration, one component of which has a greater shrinking potential than the other, thus leading to helical crimping and bulking on heat treatment.

It is necessary for the film which is to be fibrillated to be drawn to effect molecular orientation and introduce a degree of fissility prior to the fibrillation step. In some cases, however, when using a striated film, particularly when a fine denier yarn is to be prepared, it is feasible to fibrillate a partially drawn film, ply and twist the resultant yarn with a roving and then draw the yarn once again after playing and twisting. This sequence of steps permits the roving to be drafted concurrently with the drawing of the filaments and a much finer denier yarn can be prepared more easily than is the case if a smaller roving had been employed with previously drawn filaments.

The fibrillated films employed in the process of this invention to prepare yarns can be made from any of the known film forming polymers. This include polyolefins, acrylics, polyamides, and polyesters, e.g. The film can also be a composite of two different polymers or two different forms of the same polymer. Such bicomponent configuration leads to improved bulk and other modifications of the properties of the surface yarn.

The staple fiber roving can be of any textile material, either natural or synthetic. Thus, cotton, wool or silk staple can be employed as well as any of the synthetic fiber formers, either the same as that in the continuous filaments or different therefrom. The preferred staple fiber roving is a natural fiber such as cotton or wool,

What l claim and desire to protect by Letters Patent is:

l. A method of preparing a blended yarn which comprises plying a fibrillated uniaxially drawn film and a substantially twist-free staple fiber roving and thereafter twisting said plied structure whereby the roving is ensheathed within the fibrillated film.

2. The method of claim 1 wherein the fibrillated uniaxially drawn film is a fibrillated uniaxially drawn striated film.

3. The method of claim 2 including the additional step of subjecting the plied and twisted structure to additional drawmg.

4. A method of preparing a blended yarn which comprises plying a fibrillated, uniaxially drawn film and a substantially twist-free staple fiber roving, twisting said plied structure whereby the roving is ensheather within the fibrillated film and thereafter subjecting the plied and twisted structure to the action of a high-velocity fluid jet to disintegrate the staple fiber roving and entangle said staple fibers with the fibrillated film.

5. The method of claim 4 wherein the fibrillated, uniaxially drawn film is a striated film.

g;;g tNiTED STATES PATENT @FFICE CER'HFICATE GE QQRREQTWN ;Patent No. 3,631,666 Dated January 4, 1972 Inventor(s) Charles W. Kim (Case 9) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 17, constitute should read constituent Column 2, line 43, multply should read multi-ply Column 4, line 11, ensheather should read ensheathed Signed and sealed this 30th day of May 1972.

(SEAL) Attest:

T QI JWARI D TLFLETQHER,JR. ROBERT GOTTSCHALK ALZ'CGSBlUfl; Officer Commissioner of Patents 

1. A method of preparing a blended yarn which comprises plying a fibrillated uniaxially drawn film and a substantially twist-free staple fiber roving and thereafter twisting said plied structure whereby the roving is ensheathed within the fibrillated film.
 2. The method of claim 1 wherein the fibrillated uniaxially drawn film is a fibrillated uniaxially drawn striated film.
 3. The method of claim 2 including the additional step of subjecting the plied and twisted structure to additional drawing.
 4. A method of preparing a blended yarn which comprises plying a fibrillated, uniaxially drawn film and a substantially twist-free staple fiber roving, twisting said plied structure whereby the roving is ensheather within the fibrillated film and thereafter subjecting the plied and twisted structure to the action of a high-velocity fluid jet to disintegrate the staple fiber roving and entangle said staple fibers with the fibrillated film.
 5. The method of claim 4 wherein the fibrillated, uniaxially drawn film is a striated film. 